Table 1. Activity of efflux pumps and half maximal inhibitory concentration (IC50) of Dox and DoxAu for feline fibrosarcoma cell lines (FFS1WAW, FFS1, FFS3, FFS5).

cell line	IC50 Dox (μg/ml)	IC50 Au-GSH-Dox* (μg/ml)	Activity of efflux pumps (after inhibition with 10 μM and 20 μM verapamil)
FFS1WAW	69.66	30.617 (p<0.05)	53
FFS1	35.39	2.815 (p<0.001)	385
FFS3	18.09	2.567 (p<0.001)	541
FFS5	8.67	10.218 (p = 0)	0

*IC50Au-GSH-Dox = IC50 of bound Dox in the Au-GSH-Dox

p values—compared IC50 of bound Dox in the Au-GSH-Dox to IC50 of free Dox